1. Field of the Invention
The present invention relates to a tool grinding machine for grinding cutting edges of tools (punch and die, in particular) by which a sheet metal can be processed.
2. Description of the Prior Art
Conventionally, a punch press such as turret press for punching a sheet metal, for instance is so far well known. In the punch press, various punches and dies are used to punch a sheet metal into various shapes.
When workpiece is punched out by use of these punches and dies, since the cutting edges of these punches and the dies are worn off or damaged as a matter of course, the processing precision is deteriorated. Therefore, whenever the worker notices the damage of the punches and the dies, the cutting edges thereof must be grounded for further use.
In the known grinding machines for grinding the cutting edges of punches and dies, punches and dies are fixed to a fixed workpiece table, and a grinding stone head having a rotating grinding stone is moved in the right and left direction and further in the upper and lower direction; or else a grinding stone head having the rotatable grinding stone is fixed, and the workpiece table is moved in the right and left direction and further in the upper and lower direction.
In the conventional grinding machines as described above, however, when the cutting edge of a punch is required to be ground, for instance, there exists a problem in that a punch body must be disassembled or removed from a punch assembly and in addition the removed punch body must be assembled with the punch assembly after grinding.
Further, when the cutting edge of a die is ground, although the upper surface of the die can be ground easily, since the rounded edge formed at the upper surface shoulder portion must be ground manually by the worker after the die upper surface has been ground, thus causing a problem in that time and labor are required.
Further, as the typical shapes of the punch and the die, although there are various shapes such as convex type, concave type, convex shear type, concave shear type, etc,. since the grinding conditions differ according to the shapes, the worker must change the grinding conditions on all such occasions before grinding the punch and die, so that there exists a problem in that the grinding workpiece is troublesome.